While a high-profile battle rages over a mosque near ground zero in Manhattan, heated confrontations have also broken out in communities across the country where mosques are proposed for far less hallowed locations.

In Murfreesboro, Tenn., Republican candidates have denounced plans for a large Muslim center proposed near a subdivision, and hundreds of protesters have turned out for a march and a county meeting.

In late June, in Temecula, Calif., members of a local Tea Party group took dogs and picket signs to Friday prayers at a mosque that is seeking to build a new worship center on a vacant lot nearby.

In Sheboygan, Wis., a few Christian ministers led a noisy fight against a Muslim group that sought permission to open a mosque in a former health food store bought by a Muslim doctor.

At one time, neighbors who did not want mosques in their backyards said their concerns were over traffic, parking and noise — the same reasons they might object to a church or a synagogue. But now the gloves are off.

In all of the recent conflicts, opponents have said their problem is Islam itself. They quote passages from the Koran and argue that even the most Americanized Muslim secretly wants to replace the Constitution with Islamic Shariah law.

These local skirmishes make clear that there is now widespread debate about whether the best way to uphold America’s democratic values is to allow Muslims the same religious freedom enjoyed by other Americans, or to pull away the welcome mat from a faith seen as a singular threat.

“What’s different is the heat, the volume, the level of hostility,” said Ihsan Bagby, associate professor of Islamic studies at the University of Kentucky. “It’s one thing to oppose a mosque because traffic might increase, but it’s different when you say these mosques are going to be nurturing terrorist bombers, that Islam is invading, that civilization is being undermined by Muslims.”

Feeding the resistance is a growing cottage industry of authors and bloggers — some of them former Muslims — who are invited to speak at rallies, sell their books and testify in churches. Their message is that Islam is inherently violent and incompatible with America.

But they have not gone unanswered. In each community, interfaith groups led by Protestant ministers, Catholic priests, rabbis and clergy members of other faiths have defended the mosques. Often, they have been slower to organize than the mosque opponents, but their numbers have usually been larger.

The mosque proposed for the site near ground zero in Lower Manhattan cleared a final hurdle last week before the city’s Landmarks Preservation Commission, and Mayor Michael R. Bloomberg hailed the decision with a forceful speech on religious liberty. While an array of religious groups supported the project, opponents included the Anti-Defamation League, an influential Jewish group, and prominent Republicans like Sarah Palin and Newt Gingrich, the former House speaker.

A smaller controversy is occurring in Temecula, about 60 miles north of San Diego, involving a typical stew of religion, politics and anti-immigrant sentiment. A Muslim community has been there for about 12 years and expanded to 150 families who have outgrown their makeshift worship space in a warehouse, said Mahmoud Harmoush, the imam, a lecturer at California State University, San Bernardino. The group wants to build a 25,000-square-foot center, with space for classrooms and a playground, on a lot it bought in 2000.

Mr. Harmoush said the Muslim families had contributed to the local food bank, sent truckloads of supplies to New Orleans after Hurricane Katrina, and participated in music nights and Thanksgiving events with the local interfaith council.

“We do all these activities and nobody notices,” he said. “Now that we have to build our center, everybody jumps to make it an issue.”

Recently, a small group of activists became alarmed about the mosque. Diana Serafin, a grandmother who lost her job in tech support this year, said she reached out to others she knew from attending Tea Party events and anti-immigration rallies. She said they read books by critics of Islam, including former Muslims like Walid Shoebat, Wafa Sultan and Manoucher Bakh. She also attended a meeting of the local chapter of ACT! for America, a Florida-based group that says its purpose is to defend Western civilization against Islam.

“As a mother and a grandmother, I worry,” Ms. Serafin said. “I learned that in 20 years with the rate of the birth population, we will be overtaken by Islam, and their goal is to get people in Congress and the Supreme Court to see that Shariah is implemented. My children and grandchildren will have to live under that.”

“I do believe everybody has a right to freedom of religion,” she said. “But Islam is not about a religion. It’s a political government, and it’s 100 percent against our Constitution.”

Ms. Serafin was among an estimated 20 to 30 people who turned out to protest the mosque, including some who intentionally took dogs to offend those Muslims who consider dogs to be ritually unclean. But they were outnumbered by at least 75 supporters. The City of Temecula recently postponed a hearing on whether to grant the mosque a permit.

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Larry Slusser, a Mormon and the secretary of the Interfaith Council of Murietta and Temecula, went to the protest to support the Muslim group. “I know them,” he said. “They’re good people. They have no ill intent. They’re good Americans. They are leaders in their professions.”

Of the protesters, he said, “they have fear because they don’t know them.”

Religious freedom is also at stake, Mr. Slusser said, adding, “They’re Americans, they deserve to have a place to worship just like everybody else.”

There are about 1,900 mosques in the United States, which run the gamut from makeshift prayer rooms in storefronts and houses to large buildings with adjoining community centers, according to a preliminary survey by Mr. Bagby, who conducted a mosque study 10 years ago and is now undertaking another.

A two-year study by a group of academics on American Muslims and terrorism concluded that contemporary mosques are actually a deterrent to the spread of militant Islam and terrorism. The study was conducted by professors with Duke’s Sanford School of Public Policy and the University of North Carolina. It disclosed that many mosque leaders had put significant effort into countering extremism by building youth programs, sponsoring antiviolence forums and scrutinizing teachers and texts.

Radicalization of alienated Muslim youths is a real threat, Mr. Bagby said. “But the youth we worry about,” he said, “are not the youth that come to the mosque.”

In central Tennessee, the mosque in Murfreesboro is the third one in the last year to encounter resistance. It became a political issue when Republican candidates for governor and Congress declared their opposition. (They were defeated in primary elections on Thursday.)

A group called Former Muslims United put up a billboard saying “Stop the Murfreesboro Mosque.” The group’s president is Nonie Darwish, also the founder of Arabs for Israel, who spoke against Islam in Murfreesboro at a fund-raising dinner for International Christian Embassy Jerusalem.

“A mosque is not just a place for worship,” Ms. Darwish said in an interview. “It’s a place where war is started, where commandments to do jihad start, where incitements against non-Muslims occur. It’s a place where ammunition was stored.”

Camie Ayash, a spokeswoman for the Islamic Center of Murfreesboro, lamented that people were listening to what she called “total disinformation” on Islam.

She said her group was stunned when what began as one person raising zoning questions about the new mosque evolved into mass protests with marchers waving signs about Shariah.

“A lot of Muslims came to the U.S. because they respect the Constitution,” she said. “There’s no conflict with the U.S. Constitution in Shariah law. If there were, Muslims wouldn’t be living here.”

In Wisconsin, the conflict over the mosque was settled when the Town Executive Council voted unanimously to give the Islamic Society of Sheboygan a permit to use the former health food store as a prayer space.

Dr. Mansoor Mirza, the physician who owns the property, said he was trying to take the long view of the controversy.

“Every new group coming to this country — Jews, Catholics, Irish, Germans, Japanese — has gone through this,” Dr. Mirza said. “Now I think it’s our turn to pay the price, and eventually we will be coming out of this, too.”

Correction: August 15, 2010

An article last Sunday about the growing resistance to new and expanded mosques in the United States misidentified the sponsor of an event where Nonie Darwish, the founder of Arabs for Israel, spoke. The event, in Murfreesboro, Tenn., was sponsored by the International Christian Embassy Jerusalem, not by Christians United for Israel.

A version of this article appears in print on August 8, 2010, on Page A1 of the New York edition with the headline: Around Country, Mosque Projects Meet Opposition. Order Reprints|Today's Paper|Subscribe